Ian Simplification

Percentage Accurate: 6.9% → 8.4%
Time: 42.0s
Alternatives: 6
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (- (/ PI 2.0) (* 2.0 (asin (sqrt (/ (- 1.0 x) 2.0))))))
double code(double x) {
	return (((double) M_PI) / 2.0) - (2.0 * asin(sqrt(((1.0 - x) / 2.0))));
}
public static double code(double x) {
	return (Math.PI / 2.0) - (2.0 * Math.asin(Math.sqrt(((1.0 - x) / 2.0))));
}
def code(x):
	return (math.pi / 2.0) - (2.0 * math.asin(math.sqrt(((1.0 - x) / 2.0))))
function code(x)
	return Float64(Float64(pi / 2.0) - Float64(2.0 * asin(sqrt(Float64(Float64(1.0 - x) / 2.0)))))
end
function tmp = code(x)
	tmp = (pi / 2.0) - (2.0 * asin(sqrt(((1.0 - x) / 2.0))));
end
code[x_] := N[(N[(Pi / 2.0), $MachinePrecision] - N[(2.0 * N[ArcSin[N[Sqrt[N[(N[(1.0 - x), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 6 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 6.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (- (/ PI 2.0) (* 2.0 (asin (sqrt (/ (- 1.0 x) 2.0))))))
double code(double x) {
	return (((double) M_PI) / 2.0) - (2.0 * asin(sqrt(((1.0 - x) / 2.0))));
}
public static double code(double x) {
	return (Math.PI / 2.0) - (2.0 * Math.asin(Math.sqrt(((1.0 - x) / 2.0))));
}
def code(x):
	return (math.pi / 2.0) - (2.0 * math.asin(math.sqrt(((1.0 - x) / 2.0))))
function code(x)
	return Float64(Float64(pi / 2.0) - Float64(2.0 * asin(sqrt(Float64(Float64(1.0 - x) / 2.0)))))
end
function tmp = code(x)
	tmp = (pi / 2.0) - (2.0 * asin(sqrt(((1.0 - x) / 2.0))));
end
code[x_] := N[(N[(Pi / 2.0), $MachinePrecision] - N[(2.0 * N[ArcSin[N[Sqrt[N[(N[(1.0 - x), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)
\end{array}

Alternative 1: 8.4% accurate, 0.2× speedup?

\[\begin{array}{l} \\ {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, -2 \cdot \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)} \end{array} \]
(FPCore (x)
 :precision binary64
 (*
  (pow
   (cbrt
    (cbrt
     (pow
      (fma PI 0.5 (* (- (* PI 0.5) (acos (sqrt (+ 0.5 (* x -0.5))))) -2.0))
      2.0)))
   3.0)
  (cbrt (fma PI 0.5 (* -2.0 (asin (sqrt (- 0.5 (* 0.5 x)))))))))
double code(double x) {
	return pow(cbrt(cbrt(pow(fma(((double) M_PI), 0.5, (((((double) M_PI) * 0.5) - acos(sqrt((0.5 + (x * -0.5))))) * -2.0)), 2.0))), 3.0) * cbrt(fma(((double) M_PI), 0.5, (-2.0 * asin(sqrt((0.5 - (0.5 * x)))))));
}
function code(x)
	return Float64((cbrt(cbrt((fma(pi, 0.5, Float64(Float64(Float64(pi * 0.5) - acos(sqrt(Float64(0.5 + Float64(x * -0.5))))) * -2.0)) ^ 2.0))) ^ 3.0) * cbrt(fma(pi, 0.5, Float64(-2.0 * asin(sqrt(Float64(0.5 - Float64(0.5 * x))))))))
end
code[x_] := N[(N[Power[N[Power[N[Power[N[Power[N[(Pi * 0.5 + N[(N[(N[(Pi * 0.5), $MachinePrecision] - N[ArcCos[N[Sqrt[N[(0.5 + N[(x * -0.5), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision], 1/3], $MachinePrecision], 1/3], $MachinePrecision], 3.0], $MachinePrecision] * N[Power[N[(Pi * 0.5 + N[(-2.0 * N[ArcSin[N[Sqrt[N[(0.5 - N[(0.5 * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
{\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, -2 \cdot \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)}
\end{array}
Derivation
  1. Initial program 9.2%

    \[\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. add-cube-cbrt9.2%

      \[\leadsto \color{blue}{\left(\sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)} \cdot \sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right) \cdot \sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}} \]
    2. pow39.2%

      \[\leadsto \color{blue}{{\left(\sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right)}^{3}} \]
  4. Applied egg-rr9.2%

    \[\leadsto \color{blue}{{\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}\right)}^{3}} \]
  5. Step-by-step derivation
    1. add-cube-cbrt9.2%

      \[\leadsto {\color{blue}{\left(\left(\sqrt[3]{\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}} \cdot \sqrt[3]{\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}}\right) \cdot \sqrt[3]{\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}}\right)}}^{3} \]
    2. unpow-prod-down9.2%

      \[\leadsto \color{blue}{{\left(\sqrt[3]{\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}} \cdot \sqrt[3]{\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}}\right)}^{3} \cdot {\left(\sqrt[3]{\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}}\right)}^{3}} \]
  6. Applied egg-rr9.2%

    \[\leadsto \color{blue}{{\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)}} \]
  7. Step-by-step derivation
    1. asin-acos10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \color{blue}{\left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)} \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    2. sub-neg10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{\color{blue}{0.5 + \left(-0.5 \cdot x\right)}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    3. *-commutative10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{0.5 + \left(-\color{blue}{x \cdot 0.5}\right)}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    4. sub-neg10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{\color{blue}{0.5 - x \cdot 0.5}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    5. div-inv10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\color{blue}{\pi \cdot \frac{1}{2}} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    6. metadata-eval10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot \color{blue}{0.5} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    7. sub-neg10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\color{blue}{0.5 + \left(-x \cdot 0.5\right)}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    8. *-commutative10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + \left(-\color{blue}{0.5 \cdot x}\right)}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    9. sub-neg10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\color{blue}{0.5 - 0.5 \cdot x}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    10. sub-neg10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\color{blue}{0.5 + \left(-0.5 \cdot x\right)}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    11. *-commutative10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + \left(-\color{blue}{x \cdot 0.5}\right)}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    12. distribute-rgt-neg-in10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + \color{blue}{x \cdot \left(-0.5\right)}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
    13. metadata-eval10.6%

      \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + x \cdot \color{blue}{-0.5}}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
  8. Applied egg-rr10.6%

    \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \color{blue}{\left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right)\right)} \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) \cdot -2\right)} \]
  9. Final simplification10.6%

    \[\leadsto {\left(\sqrt[3]{\sqrt[3]{{\left(\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right)\right) \cdot -2\right)\right)}^{2}}}\right)}^{3} \cdot \sqrt[3]{\mathsf{fma}\left(\pi, 0.5, -2 \cdot \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)} \]
  10. Add Preprocessing

Alternative 2: 8.4% accurate, 0.5× speedup?

\[\begin{array}{l} \\ {\left(\sqrt[3]{\pi \cdot 0.5 + -2 \cdot \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)}\right)}^{3} \end{array} \]
(FPCore (x)
 :precision binary64
 (pow
  (cbrt (+ (* PI 0.5) (* -2.0 (- (* PI 0.5) (acos (sqrt (- 0.5 (* 0.5 x))))))))
  3.0))
double code(double x) {
	return pow(cbrt(((((double) M_PI) * 0.5) + (-2.0 * ((((double) M_PI) * 0.5) - acos(sqrt((0.5 - (0.5 * x)))))))), 3.0);
}
public static double code(double x) {
	return Math.pow(Math.cbrt(((Math.PI * 0.5) + (-2.0 * ((Math.PI * 0.5) - Math.acos(Math.sqrt((0.5 - (0.5 * x)))))))), 3.0);
}
function code(x)
	return cbrt(Float64(Float64(pi * 0.5) + Float64(-2.0 * Float64(Float64(pi * 0.5) - acos(sqrt(Float64(0.5 - Float64(0.5 * x)))))))) ^ 3.0
end
code[x_] := N[Power[N[Power[N[(N[(Pi * 0.5), $MachinePrecision] + N[(-2.0 * N[(N[(Pi * 0.5), $MachinePrecision] - N[ArcCos[N[Sqrt[N[(0.5 - N[(0.5 * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 1/3], $MachinePrecision], 3.0], $MachinePrecision]
\begin{array}{l}

\\
{\left(\sqrt[3]{\pi \cdot 0.5 + -2 \cdot \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)}\right)}^{3}
\end{array}
Derivation
  1. Initial program 9.2%

    \[\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. add-cube-cbrt9.2%

      \[\leadsto \color{blue}{\left(\sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)} \cdot \sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right) \cdot \sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}} \]
    2. pow39.2%

      \[\leadsto \color{blue}{{\left(\sqrt[3]{\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right)}^{3}} \]
  4. Applied egg-rr9.2%

    \[\leadsto \color{blue}{{\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right) \cdot -2\right)}\right)}^{3}} \]
  5. Step-by-step derivation
    1. asin-acos10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \color{blue}{\left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right)} \cdot -2\right)}\right)}^{3} \]
    2. div-inv10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\color{blue}{\pi \cdot \frac{1}{2}} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \cdot -2\right)}\right)}^{3} \]
    3. metadata-eval10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot \color{blue}{0.5} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \cdot -2\right)}\right)}^{3} \]
    4. *-commutative10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 - \color{blue}{0.5 \cdot x}}\right)\right) \cdot -2\right)}\right)}^{3} \]
    5. cancel-sign-sub-inv10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\color{blue}{0.5 + \left(-0.5\right) \cdot x}}\right)\right) \cdot -2\right)}\right)}^{3} \]
    6. metadata-eval10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + \color{blue}{-0.5} \cdot x}\right)\right) \cdot -2\right)}\right)}^{3} \]
    7. *-commutative10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 + \color{blue}{x \cdot -0.5}}\right)\right) \cdot -2\right)}\right)}^{3} \]
    8. +-commutative10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\color{blue}{x \cdot -0.5 + 0.5}}\right)\right) \cdot -2\right)}\right)}^{3} \]
    9. fma-define10.5%

      \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\color{blue}{\mathsf{fma}\left(x, -0.5, 0.5\right)}}\right)\right) \cdot -2\right)}\right)}^{3} \]
  6. Applied egg-rr10.5%

    \[\leadsto {\left(\sqrt[3]{\mathsf{fma}\left(\pi, 0.5, \color{blue}{\left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{\mathsf{fma}\left(x, -0.5, 0.5\right)}\right)\right)} \cdot -2\right)}\right)}^{3} \]
  7. Taylor expanded in x around inf 10.5%

    \[\leadsto {\left(\sqrt[3]{\color{blue}{-2 \cdot \left(0.5 \cdot \pi - \cos^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right) + 0.5 \cdot \pi}}\right)}^{3} \]
  8. Final simplification10.5%

    \[\leadsto {\left(\sqrt[3]{\pi \cdot 0.5 + -2 \cdot \left(\pi \cdot 0.5 - \cos^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right)\right)}\right)}^{3} \]
  9. Add Preprocessing

Alternative 3: 8.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\pi}{2} + 2 \cdot \left(\cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right) - \frac{\pi}{2}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (+ (/ PI 2.0) (* 2.0 (- (acos (sqrt (+ 0.5 (* x -0.5)))) (/ PI 2.0)))))
double code(double x) {
	return (((double) M_PI) / 2.0) + (2.0 * (acos(sqrt((0.5 + (x * -0.5)))) - (((double) M_PI) / 2.0)));
}
public static double code(double x) {
	return (Math.PI / 2.0) + (2.0 * (Math.acos(Math.sqrt((0.5 + (x * -0.5)))) - (Math.PI / 2.0)));
}
def code(x):
	return (math.pi / 2.0) + (2.0 * (math.acos(math.sqrt((0.5 + (x * -0.5)))) - (math.pi / 2.0)))
function code(x)
	return Float64(Float64(pi / 2.0) + Float64(2.0 * Float64(acos(sqrt(Float64(0.5 + Float64(x * -0.5)))) - Float64(pi / 2.0))))
end
function tmp = code(x)
	tmp = (pi / 2.0) + (2.0 * (acos(sqrt((0.5 + (x * -0.5)))) - (pi / 2.0)));
end
code[x_] := N[(N[(Pi / 2.0), $MachinePrecision] + N[(2.0 * N[(N[ArcCos[N[Sqrt[N[(0.5 + N[(x * -0.5), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] - N[(Pi / 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{2} + 2 \cdot \left(\cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right) - \frac{\pi}{2}\right)
\end{array}
Derivation
  1. Initial program 9.2%

    \[\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. asin-acos10.5%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \color{blue}{\left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right)} \]
    2. add-cube-cbrt8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\frac{\color{blue}{\left(\sqrt[3]{\pi} \cdot \sqrt[3]{\pi}\right) \cdot \sqrt[3]{\pi}}}{2} - \cos^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right) \]
    3. associate-/l*8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\color{blue}{\left(\sqrt[3]{\pi} \cdot \sqrt[3]{\pi}\right) \cdot \frac{\sqrt[3]{\pi}}{2}} - \cos^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right) \]
    4. fma-neg8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \color{blue}{\mathsf{fma}\left(\sqrt[3]{\pi} \cdot \sqrt[3]{\pi}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right)} \]
    5. pow28.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \mathsf{fma}\left(\color{blue}{{\left(\sqrt[3]{\pi}\right)}^{2}}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right) \]
    6. div-sub8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \mathsf{fma}\left({\left(\sqrt[3]{\pi}\right)}^{2}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{\color{blue}{\frac{1}{2} - \frac{x}{2}}}\right)\right) \]
    7. metadata-eval8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \mathsf{fma}\left({\left(\sqrt[3]{\pi}\right)}^{2}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{\color{blue}{0.5} - \frac{x}{2}}\right)\right) \]
    8. div-inv8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \mathsf{fma}\left({\left(\sqrt[3]{\pi}\right)}^{2}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{0.5 - \color{blue}{x \cdot \frac{1}{2}}}\right)\right) \]
    9. metadata-eval8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \mathsf{fma}\left({\left(\sqrt[3]{\pi}\right)}^{2}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{0.5 - x \cdot \color{blue}{0.5}}\right)\right) \]
  4. Applied egg-rr8.3%

    \[\leadsto \frac{\pi}{2} - 2 \cdot \color{blue}{\mathsf{fma}\left({\left(\sqrt[3]{\pi}\right)}^{2}, \frac{\sqrt[3]{\pi}}{2}, -\cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right)} \]
  5. Step-by-step derivation
    1. fma-neg8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \color{blue}{\left({\left(\sqrt[3]{\pi}\right)}^{2} \cdot \frac{\sqrt[3]{\pi}}{2} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right)} \]
    2. associate-*r/8.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\color{blue}{\frac{{\left(\sqrt[3]{\pi}\right)}^{2} \cdot \sqrt[3]{\pi}}{2}} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \]
    3. unpow28.3%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\frac{\color{blue}{\left(\sqrt[3]{\pi} \cdot \sqrt[3]{\pi}\right)} \cdot \sqrt[3]{\pi}}{2} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \]
    4. rem-3cbrt-lft10.5%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\frac{\color{blue}{\pi}}{2} - \cos^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)\right) \]
    5. sub-neg10.5%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{\color{blue}{0.5 + \left(-x \cdot 0.5\right)}}\right)\right) \]
    6. distribute-rgt-neg-in10.5%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{0.5 + \color{blue}{x \cdot \left(-0.5\right)}}\right)\right) \]
    7. metadata-eval10.5%

      \[\leadsto \frac{\pi}{2} - 2 \cdot \left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{0.5 + x \cdot \color{blue}{-0.5}}\right)\right) \]
  6. Simplified10.5%

    \[\leadsto \frac{\pi}{2} - 2 \cdot \color{blue}{\left(\frac{\pi}{2} - \cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right)\right)} \]
  7. Final simplification10.5%

    \[\leadsto \frac{\pi}{2} + 2 \cdot \left(\cos^{-1} \left(\sqrt{0.5 + x \cdot -0.5}\right) - \frac{\pi}{2}\right) \]
  8. Add Preprocessing

Alternative 4: 6.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \end{array} \]
(FPCore (x)
 :precision binary64
 (- (/ PI 2.0) (* 2.0 (asin (sqrt (/ (- 1.0 x) 2.0))))))
double code(double x) {
	return (((double) M_PI) / 2.0) - (2.0 * asin(sqrt(((1.0 - x) / 2.0))));
}
public static double code(double x) {
	return (Math.PI / 2.0) - (2.0 * Math.asin(Math.sqrt(((1.0 - x) / 2.0))));
}
def code(x):
	return (math.pi / 2.0) - (2.0 * math.asin(math.sqrt(((1.0 - x) / 2.0))))
function code(x)
	return Float64(Float64(pi / 2.0) - Float64(2.0 * asin(sqrt(Float64(Float64(1.0 - x) / 2.0)))))
end
function tmp = code(x)
	tmp = (pi / 2.0) - (2.0 * asin(sqrt(((1.0 - x) / 2.0))));
end
code[x_] := N[(N[(Pi / 2.0), $MachinePrecision] - N[(2.0 * N[ArcSin[N[Sqrt[N[(N[(1.0 - x), $MachinePrecision] / 2.0), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)
\end{array}
Derivation
  1. Initial program 9.2%

    \[\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  2. Add Preprocessing
  3. Final simplification9.2%

    \[\leadsto \frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  4. Add Preprocessing

Alternative 5: 3.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \pi \cdot 0.5 + 2 \cdot \sin^{-1} \left(\sqrt{0.5}\right) \end{array} \]
(FPCore (x) :precision binary64 (+ (* PI 0.5) (* 2.0 (asin (sqrt 0.5)))))
double code(double x) {
	return (((double) M_PI) * 0.5) + (2.0 * asin(sqrt(0.5)));
}
public static double code(double x) {
	return (Math.PI * 0.5) + (2.0 * Math.asin(Math.sqrt(0.5)));
}
def code(x):
	return (math.pi * 0.5) + (2.0 * math.asin(math.sqrt(0.5)))
function code(x)
	return Float64(Float64(pi * 0.5) + Float64(2.0 * asin(sqrt(0.5))))
end
function tmp = code(x)
	tmp = (pi * 0.5) + (2.0 * asin(sqrt(0.5)));
end
code[x_] := N[(N[(Pi * 0.5), $MachinePrecision] + N[(2.0 * N[ArcSin[N[Sqrt[0.5], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\pi \cdot 0.5 + 2 \cdot \sin^{-1} \left(\sqrt{0.5}\right)
\end{array}
Derivation
  1. Initial program 9.2%

    \[\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. sub-neg9.2%

      \[\leadsto \color{blue}{\frac{\pi}{2} + \left(-2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right)} \]
    2. +-commutative9.2%

      \[\leadsto \color{blue}{\left(-2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)\right) + \frac{\pi}{2}} \]
    3. add-cube-cbrt8.5%

      \[\leadsto \left(-\color{blue}{\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)} \cdot \sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right) \cdot \sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}}\right) + \frac{\pi}{2} \]
    4. distribute-rgt-neg-in8.5%

      \[\leadsto \color{blue}{\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)} \cdot \sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right) \cdot \left(-\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}\right)} + \frac{\pi}{2} \]
    5. fma-define8.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)} \cdot \sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}, -\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right)}, \frac{\pi}{2}\right)} \]
  4. Applied egg-rr8.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left({\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2}, -\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}, \pi \cdot 0.5\right)} \]
  5. Step-by-step derivation
    1. add-sqr-sqrt0.0%

      \[\leadsto \mathsf{fma}\left({\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2}, \color{blue}{\sqrt{-\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}} \cdot \sqrt{-\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}}}, \pi \cdot 0.5\right) \]
    2. sqrt-unprod3.6%

      \[\leadsto \mathsf{fma}\left({\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2}, \color{blue}{\sqrt{\left(-\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right) \cdot \left(-\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}}, \pi \cdot 0.5\right) \]
    3. sqr-neg3.6%

      \[\leadsto \mathsf{fma}\left({\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2}, \sqrt{\color{blue}{\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)} \cdot \sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}}}, \pi \cdot 0.5\right) \]
    4. sqrt-prod3.6%

      \[\leadsto \mathsf{fma}\left({\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2}, \color{blue}{\sqrt{\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}} \cdot \sqrt{\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}}}, \pi \cdot 0.5\right) \]
    5. add-sqr-sqrt3.6%

      \[\leadsto \mathsf{fma}\left({\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2}, \color{blue}{\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}}, \pi \cdot 0.5\right) \]
    6. fma-define3.6%

      \[\leadsto \color{blue}{{\left(\sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)}\right)}^{2} \cdot \sqrt[3]{2 \cdot \sin^{-1} \left(\sqrt{0.5 - x \cdot 0.5}\right)} + \pi \cdot 0.5} \]
  6. Applied egg-rr3.6%

    \[\leadsto \color{blue}{2 \cdot \sin^{-1} \left(\sqrt{0.5 - 0.5 \cdot x}\right) + \pi \cdot 0.5} \]
  7. Taylor expanded in x around 0 3.6%

    \[\leadsto 2 \cdot \sin^{-1} \color{blue}{\left(\sqrt{0.5}\right)} + \pi \cdot 0.5 \]
  8. Final simplification3.6%

    \[\leadsto \pi \cdot 0.5 + 2 \cdot \sin^{-1} \left(\sqrt{0.5}\right) \]
  9. Add Preprocessing

Alternative 6: 4.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{0.5}\right) \end{array} \]
(FPCore (x) :precision binary64 (- (/ PI 2.0) (* 2.0 (asin (sqrt 0.5)))))
double code(double x) {
	return (((double) M_PI) / 2.0) - (2.0 * asin(sqrt(0.5)));
}
public static double code(double x) {
	return (Math.PI / 2.0) - (2.0 * Math.asin(Math.sqrt(0.5)));
}
def code(x):
	return (math.pi / 2.0) - (2.0 * math.asin(math.sqrt(0.5)))
function code(x)
	return Float64(Float64(pi / 2.0) - Float64(2.0 * asin(sqrt(0.5))))
end
function tmp = code(x)
	tmp = (pi / 2.0) - (2.0 * asin(sqrt(0.5)));
end
code[x_] := N[(N[(Pi / 2.0), $MachinePrecision] - N[(2.0 * N[ArcSin[N[Sqrt[0.5], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{0.5}\right)
\end{array}
Derivation
  1. Initial program 9.2%

    \[\frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{\frac{1 - x}{2}}\right) \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0 4.4%

    \[\leadsto \frac{\pi}{2} - 2 \cdot \sin^{-1} \color{blue}{\left(\sqrt{0.5}\right)} \]
  4. Final simplification4.4%

    \[\leadsto \frac{\pi}{2} - 2 \cdot \sin^{-1} \left(\sqrt{0.5}\right) \]
  5. Add Preprocessing

Developer target: 100.0% accurate, 2.1× speedup?

\[\begin{array}{l} \\ \sin^{-1} x \end{array} \]
(FPCore (x) :precision binary64 (asin x))
double code(double x) {
	return asin(x);
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = asin(x)
end function
public static double code(double x) {
	return Math.asin(x);
}
def code(x):
	return math.asin(x)
function code(x)
	return asin(x)
end
function tmp = code(x)
	tmp = asin(x);
end
code[x_] := N[ArcSin[x], $MachinePrecision]
\begin{array}{l}

\\
\sin^{-1} x
\end{array}

Reproduce

?
herbie shell --seed 2024062 
(FPCore (x)
  :name "Ian Simplification"
  :precision binary64

  :herbie-target
  (asin x)

  (- (/ PI 2.0) (* 2.0 (asin (sqrt (/ (- 1.0 x) 2.0))))))